[ALL MEMBERS] Baseband is not Bootloader is not Firmware

Tmob337 · #1 (**permalink**) 03-03-2008, 08:07 AM

Hi all,

I'm only posting this because I've seen nothing similar anywhere else. I know it's probably uselss, but g-d willing, Google will pick this up and un-confuse some folk:

Bootloader is not the same as BaseBand is not the same as Firmware.

BOOTLOADER:
Versions: 2G 3.9, 4.6 3G 5.8

What is it?

There are at least two bootloaders in the iPhone. One is called the "ARM Core Bootloader" and deals with the Operating System. The Bootloader we are interested in here is the "Baseband Bootloader." More info on the different bootloader tasks can be found here and here

A Bootloader is the mommy that goes into the iPhone's room when the iPhone is turned off and gets the iPhone awake, out of bed, and ready for school. It's main function is to make sure that the iPhone is awake before it gets out of bed, out of bed before getting bathed, bathed before getting dressed, and dressed before being taken to the bus stop. Without the bootloader, you would have a sleeping iPhone in pajamas soaked in bathwater waiting for the bus.

Bootloaders make sure that when the iPhone boots it is doing things in the right order, and getting everything done.

Like people, the iPhone keeps the same Mommy its entire life. If you bought version 3.9, you have version 3.9 no matter how many upgrades you've done.

Of course, there are rare cases where people have "step-mommies." Some people have abandoned their 4.6 mommy and adopted a 3.9 mommy. Hopefully you are aware if your phone has done this.

Why do I care?

Your bootloader version determines the kind of unlock you can perform. Because 3.9 is the easy-going, liberal mom, it will allow the dev team to do all sorts of things during the boot process. It makes the phone very accessible.

Bootloader 4.6 is a much more restricting parent. Mrs 4.6 is certain that her iPhone is going to be President someday, and is very controlling about what her iPhone can and cannot do. For example, 4.6 does not allow you to write a baseband that she can't verify.

To verify a baseband (definition below), you need the secpack. Think of this as that safety word parents and children were supposed to make up in case an uncle had to pick you up at school. Without the secpack safe-word, you can't write a hacked baseband onto the phone. Without hacking the baseband, you cannot use the unlocking method that comes with ziPhone (which I believe is the GEO-IPSF-like method. Someone please tell me if I'm wrong about that).

To get around this, ziPhone (and my favorite, Independence) offer to divorce you from your un-yielding 4.6 mother and get you a very permissive 3.9 Step-Mom. Go to one of these tutorials: http://iclarified.com/entry/index.php?enid=747
http://iclarified.com/entry/index.php?enid=737
http://www.iclarified.com/entry/index.php?enid=765

If you like your 4.6 mommy (because you really do want to be president someday) then you will have to use a soft-update method, which installs the software updates to the OS but does not update baseband. This is sometimes called the Hybrid-unlock.

Which do I have?

iPhone unlock methods are primarily interested in the "Baseband Bootloader."

These are version number 3.9 and 4.6. Original iPhones shipped with Bootloader 3.9. If you ever had firmware 1.1.1 or earlier on your phone, you have bootloader 3.9.

If you bought your iPhone in 2008, you probably have version 4.6.

BASEBAND:
Versions:
2G: 03.12.06_G, 03.14.08_G, 04.01.13_G, 04.02.13_G, 04.03.13_G, 04.04.05_G, 04.05.04_G

3G: 01.45.00, 01.48.02, 02.08.01

What is it?

The BaseBand is the iPhone's backpack.

The BaseBand controls the interaction between the Phone part of the iPhone and the operating system. In most cell phones, the Baseband chip is seperate from the phone's main hard drive and processor. I don't know if that's the case for the iPhone. The Baseband is one of those things Mrs. Bootloader checks on when she's waking up the iPhone.

Whenever the iPhone needs to talk to cell towers-- whether for voice or data-- it works through the Baseband. The Baseband is responsbile for making sure the sim-card is valid and for getting Signal.

Why would Apple do this? Why would Apple make a protected, hard to get to, locked-down area of the hardware to store the phone functions in?

Well, obviously, so that it would be protected, hard to get to, and locked-down. Want another reason? Because that's how cell phones do things. Every modern cell phone has a baseband. The functions are seperated out for the same reason that video and audio get their own cards in a computer: to maintain stability.

When the iPhone heads off to school, it needs certain things to work there. It needs notebook paper, a ruler, a calculator, a binder, etc... The Baseband has all this. As many have discovered, you can take the backpack away from a kid without it dying. You can also have a non-working baseband and still have an iPhone-- although it will behave more like an iPod Touch.

You may think you're dialing a phone when you tap a number in to the iPhone. You're not. You're creating a string of instructions. Once you hit call the OS takes your instructions and gives them to the baseband. The baseband then deactivates EDGE, sends a notice to the cell towers that it's initiating a call, provides the towers with the number being dialed, waits for the tower to send back a signal (Busy or Ringing), and once the call is connected it sends wake up signals to the microphone and the speaker of the phone. Because the baseband already knows how to do all this, the only thing the iPhone needs to do is say "Make a call with this number" and wait for the response. It doesn't have to use it's very powerful (by comparison) processor to handle these menial tasks.

Why do I care?

Right now you care because this is the difference between Locate and no Locate feature in Google Maps. In the future, other features may rely on more up-to-date Baseband code. Right now, Locate is the only "new" baseband feature.

Remember, the Baseband is handling all of the communication between the Cell Towers and the iPhone OS. Now, chances are the phone always received location data from the towers-- that's why things like Navizon work. But with version 4.03.13_G, Apple obviously added some code that simplified the process. Navizon probably has to go into the baseband and dig around to find the cell tower coordinates. With version 4.03.13_G and later, the Apple app only has to say "Tell me where we are." The baseband handles the rest and sends a location string in response.

Which do I have?

Depends on which Firmware you have. This site has a list of iPod Firmware and tells you which version Baseband was installed with each: http://www.trejan.com/projects/ipod/#FIRMWARE

FIRMWARE:
Versions: 1.0.0, 1.0.1, 1.0.2, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 2.0, 2.0.1, 2.0.2

What is it?

The Firmware is the Kid. This is everything the iPhone is-- it's soul. It's the operating system.

So, we go back above and look at everything we've said so far. When you turn on an iPhone, the Mommy/Bootloader starts getting the Kid/Firmware up and running. It makes sure all the proper Toiletries/Services are run. It loads up and attaches the Backpack/Baseband to the Kid/Firmware's back, and sends it off to school.

The Firmware for an iPhone is very flexible. Today it includes the kernel of the iPhone, the Springboard app, the mainpage iPhone apps, the ability to run the Wifi antenna, to handle getting Web Pages, etc. Under the heading of Firmware Apple can change (and does change) many things.

Why do I care?

Wiggle and Web-kits, Multiple-recipient SMS messages, Locate in Google Maps, and someday the SDK. Knowing your firmware version has been key to keeping up with the Jailbreak/Unlock saga. With each new Firmware has come elegant, desirable apps and functions that have enticed people to update-- and frustrated those who risk losing their third-party apps or sim-unlocks if they do want to update.

Which do I have?

Your Software version is listed whenever you connect your phone to iTunes. Go to the iTunes icon under Devices and click on the tab marked Summary.

Yes, it's a long post. But at least now admins and users have a place to send someone when they say they have Baseband 1.1.3 running on Firmware 3.9.

I would also like to make a post for Jailbreak/Activate/Unlock clarification. IF response to this post is positive, I will.

If any information in this post is in error, please post a comment and I will update the post to reflect reality.

-TM